Heat Transfer Behavior of Sulfur for Thermal Storage Applications

Efficient and cost-effective thermal energy storage system plays an important role in energy conservation. Elemental sulfur, the thirteenth most abundant element on earth, is actively being researched as a potential thermal storage medium due to its high energy storage density and low cost. The present work investigates the heat transfer behavior of elemental sulfur at temperatures between 50 degree Celsius and 250 degree Celsius. A shell and tube heat exchanger configuration with sulfur stored inside the tubes and heat transfer fluid flowing over the tubes through the shell is considered. A detailed computational model solving for the conjugate heat transfer and solid-liquid phase change dynamics of the sulfur based thermal energy storage system is developed to elucidate the complex interplay between the governing heat transfer and fluid flow phenomena during charge and discharge operations. The developed numerical model is compared with experimental results and a systematic parametric analysis of the effects of various design parameters on the performance of the thermal storage system is reported.